Alterations in amino acid levels and metabolite ratio of spinal cord in rat with myocardial ischemia-reperfusion injury by proton magnetic resonance spectroscopy

Abstract Objectives The mechanism behind spinal metabolites and myocardial ischemia-reperfusion (IR) injury is not well understood. Proton magnetic resonance spectroscopic analysis of spinal cord extracts provides a quick evaluation of the specific metabolic activity in rats with myocardial IR injury. We investigated the relationship between the IR-related variables and the changes in spinal metabolites. Methods Proton magnetic resonance spectroscopy (1H-MRS) was used to assess the spinal metabolites of adult rats with and without myocardial IR injury (n=6 per group). Myocardial IR injury was reproduced using intermittent occlusion of the left anterior descending coronary artery. We studied the relationship between the metabolite ratio measurement and IR-related variables. All rats underwent 1H-MRS, with the ratio of interest placed in different spinal cord segments to measure levels of twelve metabolites including N-acetylaspartate (NAA), taurine (Tau),glutamate (Glu),gamma amino acid butyric acid (GABA),creatine (Cr), and myoinositol (MI), etc. Results Rats with myocardial IR injury had higher concentration of Tau in the upper thoracic spinal cord (p< 0.05), and lower concentration of Gly and Glu in the cervical segment of the spinal cord (p< 0.05), when compared to the Control group. The ratios of glutamate/taurine (Glu/Tau), Glu/(GABA+Tau) and Glu/Total were significantly different between the IR group and the Control group in the upper thoracic spinal cord (p< 0.05). So were the ratios of Glu/(GABA+Tau) in the cervical segment (p< 0.05),and Glu/Tau and Glu/(GABA+Tau) in the lower thoracic spinal cord (p< 0.05). Conclusions These findings suggest that myocardial IR injury may be related to spinal biochemical alterations. It is speculated that these observed changes in the levels of spinal metabolites may be involved in the pathogenesis and regulation of myocardial IR injury. Keywords: myocardial ischemia-reperfusion injury; spinal cord; metabolomics; proton nuclear magnetic resonanc

Assessing the concentration and potential health risk of heavy metals in China's main deciduous fruits

AbstractTo assess levels of contamination and human health risk, we analyzed the concentrations of the heavy metals lead (Pb), cadmium (Cd), chromium (Cr), and nickel (Ni) in China's main deciduous fruits — apple, pear, peach, grape, and jujube. The concentration order of the heavy metals was Ni>Cr>Pb>Cd. In 97.5% of the samples, heavy metal concentrations were within the maximum permissible limits. Among the fruits studied, the heavy metal concentrations in jujube and peach proved to be the highest, and those in grape proved to be the lowest. Only 2.2% of the samples were polluted by Ni, only 0.4% of the samples were polluted by Pb, and no samples were polluted by Cd or Cr. Compared with the other fruits, the combined heavy metal pollution was significantly higher (P<0.05) in peach and significantly lower (P<0.05) in grape. For the combined heavy metal pollution, 96.9% of the samples were at safe level, 2.32% at warning level, 0.65% at light level, and 0.13% at moderate level. In the fruits studied, the contribution of heavy metals to the daily intake rates (DIR) followed the order of Ni>Cr>Pb>Cd. The highest DIR came from apple, while the lowest DIR came from grape. For each of the heavy metals, the total DIR from five studied fruits corresponded to no more than 1.1% of the tolerable daily intake, indicating that no significant adverse health effects are expected from the heavy metals and the fruits studied. The target hazard quotients and the total target hazard quotients demonstrated that none of the analyzed heavy metals may pose risk to consumers through the fruits studied. The highest risk was posed by apple, followed in decreasing order by peach and pear, jujube, and grape. We suggest that the main deciduous fruits (apple, pear, peach, grape, and jujube) of China's main producing areas are safe to eat

Detachment Activated CyPA/CD147 Induces Cancer Stem Cell Potential in Non-stem Breast Cancer Cells

This work is licensed under a Creative Commons Attribution 4.0 International License.Background: Cancer stem cells (CSCs), responsible for cancer metastasis and recurrence, are generated from non-CSCs after chemo-radiation therapy. This study investigated the induction of CSC potential in non-stem breast cancer cells and the underlying molecular mechanisms in detachment culture. Methods: Bulk breast cancer cells, or sorted non-CSCs and CSCs were cultured under an attached or detached condition to assess CSC numbers, ability to form tumor spheres, expression of stemness markers, and chemoresistance. Lentivirus carrying CD147 shRNA or cDNA was used to manipulate CD147 expression, while CD147 ligand recombinant cyclophilin A (CyPA) or its inhibitor was used to activate or inhibit CD147 signaling. Results: Detachment promoted anoikis resistance, chemoresistance, sphere formation, self-renewal, and expression of stemness markers in breast cancer cells. Detachment increased functional ALDH+ or CD44highCD24–/low CSCs, and induced CSC potential in ALDH– or CD44lowCD24high non-CSCs. Upon detachment, both CD147 expression and CyPA secretion were enhanced, and CyPA-CD147 activation mediated detachment induced CSC potential in non-CSCs via STAT3 signaling. Clinically, CD147 and pSTAT3 were highly co-expressed and correlated with poor overall survival and tumor recurrence in breast cancer patients. Conclusion: This study demonstrates that detachment induces the generation of CSCs from non-stem breast cancer cells via CyPA-CD147 signaling, indicating that targeting CD147 may serve as a potential novel therapeutic strategy for lethal metastatic breast cancer by eliminating induced CSCs.National Basic Research Program (#2015CB553700)National Science and Technology Major Project (#2015ZX09501-009)National Natural Science Foundation of China (#31571469 and #81872349

Molecular and biochemical characterization of key enzymes in the cysteine and serine metabolic pathways of Acanthamoeba castellanii

Abstract Background Acanthamoeba spp. can cause serious human infections, including Acanthamoeba keratitis, granulomatous amoebic encephalitis and cutaneous acanthamoebiasis. Cysteine biosynthesis and the L-serine metabolic pathway play important roles in the energy metabolism of Acanthamoeba spp. However, no study has confirmed the functions of cysteine synthase (AcCS) in the cysteine pathway and phosphoglycerate dehydrogenase (AcGDH) or phosphoserine aminotransferase (AcSPAT) in the non-phosphorylation serine metabolic pathway of Acanthamoeba. Methods The AcCS, AcGDH and AcSPAT genes were amplified by PCR, and their recombinant proteins were expressed in Escherichia coli. Polyclonal antibodies against the recombinant proteins were prepared in mice and used to determine the subcellular localisation of each native protein by confocal laser scanning microscopy. The enzymatic activity of each recombinant protein was also analysed. Furthermore, each gene expression level was analysed by quantitative PCR after treatment with different concentrations of cysteine or L-serine. Results The AcCS gene encodes a 382-amino acid protein with a predicted molecular mass of 43.1 kDa and an isoelectric point (pI) of 8.11. The AcGDH gene encodes a 350-amino acid protein with a predicted molecular mass of 39.1 kDa and a pI of 5.51. The AcSPAT gene encodes a 354-amino acid protein with a predicted molecular mass of 38.3 kDa and a pI of 6.26. Recombinant AcCS exhibited a high cysteine synthesis activity using O-acetylserine and Na2S as substrates. Both GDH and SPAT catalysed degradation, rather than synthesis, of serine. Exogenous L-serine or cysteine inhibited the expression of all three enzymes in a time- and dose-dependent manner. Conclusions This study demonstrated that AcCS participates in cysteine biosynthesis and serine degradation via the non-phosphorylation serine metabolic pathway, providing a molecular basis for the discovery of novel anti-Acanthamoeba drugs

Piper puerense, a new species of Piperaceae from Yunnan, China

Su, Fan, Ji, Xun-Zhi, Wu, Bao-Duo, Qin, Xiao-Wei, Hao, Chao-Yun (2022): Piper puerense, a new species of Piperaceae from Yunnan, China. Phytotaxa 575 (2): 159-165, DOI: 10.11646/phytotaxa.575.2.5, URL: http://dx.doi.org/10.11646/phytotaxa.575.2.

Stress analysis on large-diameter buried gas pipelines under catastrophic landslides

Abstract This paper presents a method for analysis of stress and strain of gas pipelines under the effect of horizontal catastrophic landslides. A soil spring model was used to analyze the nonlinear characteristics concerning the mutual effects between the pipeline and the soil. The Ramberg–Osgood model was used to describe the constitutive relations of pipeline materials. This paper also constructed a finite element analysis model using ABAQUS finite element software and studied the distribution of the maximum stress and strain of the pipeline and the axial stress and strain along the pipeline by referencing some typical accident cases. The calculation results indicated that the maximum stress and strain increased gradually with the displacement of landslide. The limit values of pipeline axial stress strain appeared at the junction of the landslide area and non-landslide area. The stress failure criterion was relatively more conservative than the strain failure criterion. The research results of this paper may be used as a technical reference concerning the design and safety management of large-diameter gas pipelines under the effects of catastrophic landslides